1. Once the trademark QR code is found stolen, you should take immediate action to prevent the loss from expanding.

2. Collect all evidence related to the theft of the trademark QR code, such as the identity information of the thief and the evidence of theft.

3. Report this matter to the Trademark Office, relevant law enforcement departments or lawyers' associations, and seek their help and suggestions.

4. You can seek legal aid when necessary to safeguard your rights and interests.